The ABC15 Investigators have learned new details about the deadly Yarnell Hill Fire.
The blaze killed 19 members of the Granite Mountain Hot Shots.
It burned through more than 8,400 acres and destroyed more than 100 structures before it was 100% contained on July 10.
Fire officials tell us the fire moved far more quickly than any fire they've ever dealt with.
Arizona Forestry Division spokesman Jim Paxon has worked his share of forest fires.
He helped found the Arizona Wildfire Academy and he served on the Southwest Interagency Incident Management Team for the Rodeo-Chediski Fire that consumed nearly half a million acres in 2002.
But Paxon says in 35 years of firefighting, he's never seen a fire move as fast as the Yarnell Hill Fire.
Paxon told us investigators believe the fire moved 22 feet per second.
That means the fire was "running" at a speed of 15 miles per hour when it overtook the position of the Granite Mountain Hotshots.
Jim Paxon said, "It was a tsunami event."
Experts say an average forest fire travels about 2 to 3 miles an hour but some can move as fast as 20 mph.
"You can't outrun a fire like that," Paxon added.
He says the blaze was aided by wind gusts in excess of 50 miles an hour—even worse weather conditions than what was predicted.
Recently released documents including an initial synopsis of the resources deployed the day the firefighters were killed reveal how rapidly changing weather conditions impacted the efforts to save homes in Yarnell.
Around 4 p.m. on Sunday, June 30, extensive thunderstorms and high winds around Prescott grounded air tankers and helicopters deployed to help fight the fire.
Even if the planes had been available, officials said winds were so strong air support would not have been able to help save the firefighters' lives.
Paxon revealed the day the Granite Mountain Hotshots died there were 37 other fires being fought in Arizona.
Despite weather conditions, crews were able to drop more than 115,000 gallons of retardant on the Yarnell Hill Fire on that tragic day.
The timeline made public this week gives us a better idea of what happened but a full report from fire investigators is due out in September.